Clean up HID backend and API.

device/hid/hid_connection.cc

 // Copyright (c) 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "device/hid/hid_connection.h"
 
 namespace device {
 
-HidConnection::HidConnection(HidDeviceInfo device_info)
+PendingHidReport::PendingHidReport() {}
+
+PendingHidReport::~PendingHidReport() {}
+
+PendingHidRead::PendingHidRead() {}
+
+PendingHidRead::~PendingHidRead() {}
+
+HidConnection::HidConnection(const HidDeviceInfo& device_info)
     : device_info_(device_info) {}
 
 HidConnection::~HidConnection() {}
 
-const HidDeviceInfo& HidConnection::device_info() const {
-  return device_info_;
-}
-
 }  // namespace device